Not sure how tall that kneewall is, but I would sacrifice depth on one side and frame another knee wall that gives you enough head room. You can put the back of the toilet against this, and the shower, sink, etc. Then it just becomes a standard 'one wall' style of bathroom, and walking in the order would be sink, toilet, shower. Hope this helps.

Thank you ! This is similar to what I think. We are probably boing to close the left side at 4.5 feet and build a long closet. On the other side will be sink, toilet and vanity. at the back, centered, will be a rectangular bath. I hope this will look nice :S What do you think for the colors ? I have already purchased White rectangular glossy porcelain for the floor. My worry is for the vanity and the counter. Thank you for your suggestions :)

Have you discussed the placement of things with a plumber to ensure your ideas fit in with existing plumbing and drainage and are economically viable? . I hope you are keeping all that lovely timber, it will make a nice cosy bathroom. I think I would keep your vanity timber to keep the room as large as possible visually, with a plain white top. Will your bath be freestanding or built in? Am I right in assuming it will be opposite the door? If so and it is built in, I would take the floor tiles up the side of the bath, or purchase a similar wall tile again for visual effect.

Thanks everyone ! This is a new construction, still in process, so it is not too hard to run pipes in this attic. We finally found a solution. Long closet on the left side, bath at the back wall and toilet, vanity and sink on the right side. Hope this will look nice.